-- tnt/init.lua

tnt = {}

-- Load support for MT game translation.
local S = minetest.get_translator('tnt')

-- loss probabilities array (one in X will be lost)
local loss_prob = {}

loss_prob['default:cobble'] = 3
loss_prob['default:dirt'] = 4

local tnt_radius = tonumber(minetest.settings:get('tnt_radius') or 3)

-- Fill a list with data for content IDs, after all nodes are registered
local cid_data = {}
minetest.after(0, function()
   for name, def in pairs(minetest.registered_nodes) do
      cid_data[minetest.get_content_id(name)] = {
         name = name,
         drops = def.drops,
         flammable = def.groups.flammable,
         on_blast = def.on_blast,
      }
   end
end)

local function rand_pos(center, pos, radius)
   local def
   local reg_nodes = minetest.registered_nodes
   local i = 0
   repeat
      -- Give up and use the center if this takes too long
      if i > 4 then
         pos.x, pos.z = center.x, center.z
         break
      end
      pos.x = center.x + math.random(-radius, radius)
      pos.z = center.z + math.random(-radius, radius)
      def = reg_nodes[minetest.get_node(pos).name]
      i = i + 1
   until def and not def.walkable
end

local function eject_drops(drops, pos, radius)
   local drop_pos = vector.new(pos)
   for _, item in pairs(drops) do
      local count = math.min(item:get_count(), item:get_stack_max())
      while count > 0 do
         local take = math.max(1,math.min(radius * radius,
               count,
               item:get_stack_max()))
         rand_pos(pos, drop_pos, radius)
         local dropitem = ItemStack(item)
         dropitem:set_count(take)
         local obj = minetest.add_item(drop_pos, dropitem)
         if obj then
            obj:get_luaentity().collect = true
            obj:set_acceleration({x = 0, y = -10, z = 0})
            obj:set_velocity({x = math.random(-3, 3),
                  y = math.random(0, 10),
                  z = math.random(-3, 3)})
         end
         count = count - take
      end
   end
end

local function add_drop(drops, item)
   item = ItemStack(item)
   local name = item:get_name()
   if loss_prob[name] ~= nil and math.random(1, loss_prob[name]) == 1 then
      return
   end

   local drop = drops[name]
   if drop == nil then
      drops[name] = item
   else
      drop:set_count(drop:get_count() + item:get_count())
   end
end

local basic_flame_on_construct -- cached value
local function destroy(drops, npos, cid, c_air, c_fire,
      on_blast_queue, on_construct_queue,
      ignore_protection, ignore_on_blast, owner)
   if not ignore_protection and minetest.is_protected(npos, owner) then
      return cid
   end

   local def = cid_data[cid]

   if not def then
      return c_air
   elseif not ignore_on_blast and def.on_blast then
      on_blast_queue[#on_blast_queue + 1] = {
         pos = vector.new(npos),
         on_blast = def.on_blast
      }
      return cid
      --[[
   elseif def.flammable then
      on_construct_queue[#on_construct_queue + 1] = {
         fn = basic_flame_on_construct,
         pos = vector.new(npos)
      }
      return c_fire
      --]]
   else
      local node_drops = minetest.get_node_drops(def.name, '')
      for _, item in pairs(node_drops) do
         add_drop(drops, item)
      end
      return c_air
   end
end

local function calc_velocity(pos1, pos2, old_vel, power)
   -- Avoid errors caused by a vector of zero length
   if vector.equals(pos1, pos2) then
      return old_vel
   end

   local vel = vector.direction(pos1, pos2)
   vel = vector.normalize(vel)
   vel = vector.multiply(vel, power)

   -- Divide by distance
   local dist = vector.distance(pos1, pos2)
   dist = math.max(dist, 1)
   vel = vector.divide(vel, dist)

   -- Add old velocity
   vel = vector.add(vel, old_vel)

   -- randomize it a bit
   vel = vector.add(vel, {
      x = math.random() - 0.5,
      y = math.random() - 0.5,
      z = math.random() - 0.5,
   })

   -- Limit to terminal velocity
   dist = vector.length(vel)
   if dist > 250 then
      vel = vector.divide(vel, dist / 250)
   end
   return vel
end

local function entity_physics(pos, radius, drops)
   local objs = minetest.get_objects_inside_radius(pos, radius)
   for _, obj in pairs(objs) do
      local obj_pos = obj:get_pos()
      local dist = math.max(1, vector.distance(pos, obj_pos))

      local damage = (4 / dist) * radius
      if obj:is_player() then
         -- currently the engine has no method to set
         -- player velocity. See #2960
         -- instead, we knock the player back 1.0 node, and slightly upwards
         local dir = vector.normalize(vector.subtract(obj_pos, pos))
         local moveoff = vector.multiply(dir, dist + 1.0)
         local newpos = vector.add(pos, moveoff)
         newpos = vector.add(newpos, {x = 0, y = 0.2, z = 0})
         obj:set_pos(newpos)

         obj:set_hp(obj:get_hp() - damage)
      else
         local do_damage = true
         local do_knockback = true
         local entity_drops = {}
         local luaobj = obj:get_luaentity()
         local objdef = minetest.registered_entities[luaobj.name]

         if objdef and objdef.on_blast then
            do_damage, do_knockback, entity_drops = objdef.on_blast(luaobj, damage)
         end

         if do_knockback then
            local obj_vel = obj:get_velocity()
            obj:set_velocity(calc_velocity(pos, obj_pos,
                  obj_vel, radius * 10))
         end
         if do_damage then
            if not obj:get_armor_groups().immortal then
               obj:punch(obj, 1.0, {
                  full_punch_interval = 1.0,
                  damage_groups = {fleshy = damage},
               }, nil)
            end
         end
         for _, item in pairs(entity_drops) do
            add_drop(drops, item)
         end
      end
   end
end

local function add_effects(pos, radius, drops)
   minetest.add_particle({
      pos = pos,
      velocity = vector.new(),
      acceleration = vector.new(),
      expirationtime = 0.4,
      size = radius * 10,
      collisiondetection = false,
      vertical = false,
      texture = 'tnt_boom.png',
      glow = 15,
   })
   minetest.add_particlespawner({
      amount = 64,
      time = 0.5,
      minpos = vector.subtract(pos, radius / 2),
      maxpos = vector.add(pos, radius / 2),
      minvel = {x = -10, y = -10, z = -10},
      maxvel = {x = 10, y = 10, z = 10},
      minacc = vector.new(),
      maxacc = vector.new(),
      minexptime = 1,
      maxexptime = 2.5,
      minsize = radius * 3,
      maxsize = radius * 5,
      texture = 'tnt_smoke.png',
   })

   -- we just dropped some items. Look at the items entities and pick
   -- one of them to use as texture
   local texture = 'tnt_blast.png' --fallback texture
   local most = 0
   for name, stack in pairs(drops) do
      local count = stack:get_count()
      if count > most then
         most = count
         local def = minetest.registered_nodes[name]
         if def and def.tiles and def.tiles[1] then
            texture = def.tiles[1]
         end
      end
   end

   minetest.add_particlespawner({
      amount = 64,
      time = 0.1,
      minpos = vector.subtract(pos, radius / 2),
      maxpos = vector.add(pos, radius / 2),
      minvel = {x = -3, y = 0, z = -3},
      maxvel = {x = 3, y = 5,  z = 3},
      minacc = {x = 0, y = -10, z = 0},
      maxacc = {x = 0, y = -10, z = 0},
      minexptime = 0.8,
      maxexptime = 2.0,
      minsize = radius * 0.66,
      maxsize = radius * 2,
      texture = texture,
      collisiondetection = true,
   })
end

function tnt.burn(pos, nodename)
   local name = nodename or minetest.get_node(pos).name
   local def = minetest.registered_nodes[name]
   if not def then
      return
   elseif def.on_ignite then
      def.on_ignite(pos)
   elseif minetest.get_item_group(name, 'tnt') > 0 then
      minetest.swap_node(pos, {name = name .. '_burning'})
      minetest.sound_play('tnt_ignite', {pos = pos})
      minetest.get_node_timer(pos):start(1)
   end
end

local function tnt_explode(pos, radius, ignore_protection, ignore_on_blast, owner, explode_center)
   pos = vector.round(pos)
   -- scan for adjacent TNT nodes first, and enlarge the explosion
   local vm1 = VoxelManip()
   local p1 = vector.subtract(pos, 2)
   local p2 = vector.add(pos, 2)
   local minp, maxp = vm1:read_from_map(p1, p2)
   local a = VoxelArea:new({MinEdge = minp, MaxEdge = maxp})
   local data = vm1:get_data()
   local count = 0
   local c_tnt = minetest.get_content_id('tnt:gunpowder_case')
   local c_tnt_burning = minetest.get_content_id('tnt:gunpowder_case_burning')
   local c_tnt_boom = minetest.get_content_id('tnt:boom')
   local c_air = minetest.get_content_id('air')
   -- make sure we still have explosion even when centre node isnt tnt related
   if explode_center then
      count = 1
   end

   for z = pos.z - 2, pos.z + 2 do
   for y = pos.y - 2, pos.y + 2 do
      local vi = a:index(pos.x - 2, y, z)
      for x = pos.x - 2, pos.x + 2 do
         local cid = data[vi]
         if cid == c_tnt or cid == c_tnt_boom or cid == c_tnt_burning then
            count = count + 1
            data[vi] = c_air
         end
         vi = vi + 1
      end
   end
   end

   vm1:set_data(data)
   vm1:write_to_map()

   -- recalculate new radius
   radius = math.floor(radius * math.pow(count, 1/3))

   -- perform the explosion
   local vm = VoxelManip()
   local pr = PseudoRandom(os.time())
   p1 = vector.subtract(pos, radius)
   p2 = vector.add(pos, radius)
   minp, maxp = vm:read_from_map(p1, p2)
   a = VoxelArea:new({MinEdge = minp, MaxEdge = maxp})
   data = vm:get_data()

   local drops = {}
   local on_blast_queue = {}
   local on_construct_queue = {}
   basic_flame_on_construct = minetest.registered_nodes['fire:basic_flame'].on_construct

   local c_fire = minetest.get_content_id('fire:basic_flame')
   for z = -radius, radius do
   for y = -radius, radius do
   local vi = a:index(pos.x + (-radius), pos.y + y, pos.z + z)
   for x = -radius, radius do
      local r = vector.length(vector.new(x, y, z))
      if (radius * radius) / (r * r) >= (pr:next(80, 125) / 100) then
         local cid = data[vi]
         local p = {x = pos.x + x, y = pos.y + y, z = pos.z + z}
         if cid ~= c_air then
            data[vi] = destroy(drops, p, cid, c_air, c_fire,
               on_blast_queue, on_construct_queue,
               ignore_protection, ignore_on_blast, owner)
         end
      end
      vi = vi + 1
   end
   end
   end

   vm:set_data(data)
   vm:write_to_map()
   vm:update_map()
   vm:update_liquids()

   -- call check_single_for_falling for everything within 1.5x blast radius
   for y = -radius * 1.5, radius * 1.5 do
   for z = -radius * 1.5, radius * 1.5 do
   for x = -radius * 1.5, radius * 1.5 do
      local rad = {x = x, y = y, z = z}
      local s = vector.add(pos, rad)
      local r = vector.length(rad)
      if r / radius < 1.4 then
         minetest.check_single_for_falling(s)
      end
   end
   end
   end

   for _, queued_data in pairs(on_blast_queue) do
      local dist = math.max(1, vector.distance(queued_data.pos, pos))
      local intensity = (radius * radius) / (dist * dist)
      local node_drops = queued_data.on_blast(queued_data.pos, intensity)
      if node_drops then
         for _, item in pairs(node_drops) do
            add_drop(drops, item)
         end
      end
   end

   for _, queued_data in pairs(on_construct_queue) do
      queued_data.fn(queued_data.pos)
   end

   minetest.log('action', 'TNT owned by ' .. owner .. ' detonated at ' ..
      minetest.pos_to_string(pos) .. ' with radius ' .. radius)

   return drops, radius
end

function tnt.boom(pos, def)
   def = def or {}
   def.radius = def.radius or 1
   def.damage_radius = def.damage_radius or def.radius * 2
   local meta = minetest.get_meta(pos)
   local owner = meta:get_string('owner')
   if not def.explode_center then
      minetest.set_node(pos, {name = 'tnt:boom'})
   end
   local sound = def.sound or 'tnt_explode'
   minetest.sound_play(sound, {pos = pos, gain = 2.5,
         max_hear_distance = math.min(def.radius * 20, 128)})
   local drops, radius = tnt_explode(pos, def.radius, def.ignore_protection,
         def.ignore_on_blast, owner, def.explode_center)
   -- append entity drops
   local damage_radius = (radius / math.max(1, def.radius)) * def.damage_radius
   entity_physics(pos, damage_radius, drops)
   if not def.disable_drops then
      eject_drops(drops, pos, radius)
   end
   add_effects(pos, radius, drops)
   minetest.log('action', 'A TNT explosion occurred at ' .. minetest.pos_to_string(pos) ..
      ' with radius ' .. radius)
end

minetest.register_node('tnt:boom', {
   drawtype = 'airlike',
   light_source = default.LIGHT_MAX,
   walkable = false,
   drop = '',
   groups = {dig_immediate = 3},
   -- unaffected by explosions
   on_blast = function() end,
})

minetest.register_node('tnt:gunpowder', {
   description = S('Gun Powder'),
   drawtype = 'raillike',
   paramtype = 'light',
   is_ground_content = false,
   sunlight_propagates = true,
   walkable = false,
   tiles = {
      'tnt_gunpowder_straight.png',
      'tnt_gunpowder_curved.png',
      'tnt_gunpowder_t_junction.png',
      'tnt_gunpowder_crossing.png'
   },
   inventory_image = 'tnt_gunpowder_inventory.png',
   wield_image = 'tnt_gunpowder_inventory.png',
   selection_box = {
      type = 'fixed',
      fixed = {-1/2, -1/2, -1/2, 1/2, -1/2+1/16, 1/2},
   },
   groups = {dig_immediate = 2, attached_node = 1, flammable = 5,
      connect_to_raillike = minetest.raillike_group('gunpowder')},
   sounds = default.node_sound_leaves_defaults(),

   on_punch = function(pos, node, puncher)
      if puncher:get_wielded_item():get_name() == 'default:torch' then
         if minetest.check_player_privs(puncher, { fire = true }) then
            minetest.set_node(pos, {name = 'tnt:gunpowder_burning'})
            minetest.log('action', puncher:get_player_name() ..
               ' ignites tnt:gunpowder at ' ..
               minetest.pos_to_string(pos))
         end
      end
   end,
   on_blast = function(pos, intensity)
      minetest.set_node(pos, {name = 'tnt:gunpowder_burning'})
   end,
   on_burn = function(pos)
      minetest.set_node(pos, {name = 'tnt:gunpowder_burning'})
   end,
   on_ignite = function(pos, igniter)
      minetest.set_node(pos, {name = 'tnt:gunpowder_burning'})
   end,
})

minetest.register_node('tnt:gunpowder_burning', {
   drawtype = 'raillike',
   paramtype = 'light',
   sunlight_propagates = true,
   walkable = false,
   light_source = 5,
   tiles = {{
      name = 'tnt_gunpowder_burning_straight_animated.png',
      animation = {
         type = 'vertical_frames',
         aspect_w = 16,
         aspect_h = 16,
         length = 1,
      }
   },
   {
      name = 'tnt_gunpowder_burning_curved_animated.png',
      animation = {
         type = 'vertical_frames',
         aspect_w = 16,
         aspect_h = 16,
         length = 1,
      }
   },
   {
      name = 'tnt_gunpowder_burning_t_junction_animated.png',
      animation = {
         type = 'vertical_frames',
         aspect_w = 16,
         aspect_h = 16,
         length = 1,
      }
   },
   {
      name = 'tnt_gunpowder_burning_crossing_animated.png',
      animation = {
         type = 'vertical_frames',
         aspect_w = 16,
         aspect_h = 16,
         length = 1,
      }
   }},
   selection_box = {
      type = 'fixed',
      fixed = {-1/2, -1/2, -1/2, 1/2, -1/2+1/16, 1/2},
   },
   drop = '',
   groups = {
      dig_immediate = 2,
      attached_node = 1,
      connect_to_raillike = minetest.raillike_group('gunpowder')
   },
   sounds = default.node_sound_leaves_defaults(),
   on_timer = function(pos, elapsed)
      for dx = -1, 1 do
      for dz = -1, 1 do
         if math.abs(dx) + math.abs(dz) == 1 then
            for dy = -1, 1 do
               tnt.burn({
                  x = pos.x + dx,
                  y = pos.y + dy,
                  z = pos.z + dz,
               })
            end
         end
      end
      end
      minetest.remove_node(pos)
   end,
   -- unaffected by explosions
   on_blast = function() end,
   on_construct = function(pos)
      minetest.sound_play('tnt_gunpowder_burning', {pos = pos, gain = 2})
      minetest.get_node_timer(pos):start(1)
   end,
})

minetest.register_craft({
   output = 'tnt:gunpowder 5',
   type = 'shapeless',
   recipe = {'default:coal_lump', 'default:gravel'}
})

minetest.register_craftitem('tnt:gunpowder_stick', {
   description = S('Stick of Gunpowder'),
   inventory_image = 'tnt_tnt_stick.png',
   groups = {flammable = 5},
})

minetest.register_craft({
   output = 'tnt:gunpowder_stick 2',
   recipe = {
      {'tnt:gunpowder', 'farming:string', 'tnt:gunpowder'},
      {'tnt:gunpowder', 'default:paper', 'tnt:gunpowder'},
      {'tnt:gunpowder', '', 'tnt:gunpowder'},
   }
})

minetest.register_craft({
   output = 'tnt:gunpowder_case',
   recipe = {
      {'tnt:gunpowder_stick', 'tnt:gunpowder_stick', 'tnt:gunpowder_stick'},
      {'tnt:gunpowder_stick', 'tnt:gunpowder_stick', 'tnt:gunpowder_stick'},
      {'tnt:gunpowder_stick', 'tnt:gunpowder_stick', 'tnt:gunpowder_stick'}
   }
})

minetest.register_abm({
   label = 'TNT ignition',
   nodenames = {'group:tnt', 'tnt:gunpowder'},
   neighbors = {'fire:basic_flame', 'default:lava_source', 'default:lava_flowing'},
   interval = 4,
   chance = 1,
   action = function(pos, node)
      tnt.burn(pos, node.name)
   end,
})

function tnt.register_tnt(def)
   local name
   if not def.name:find(':') then
      name = 'tnt:' .. def.name
   else
      name = def.name
      def.name = def.name:match(':([%w_]+)')
   end
   if not def.tiles then def.tiles = {} end
   local tnt_top = def.tiles.top or def.name .. '_top.png'
   local tnt_bottom = def.tiles.bottom or def.name .. '_bottom.png'
   local tnt_side = def.tiles.side or def.name .. '_side.png'
   local tnt_burning = def.tiles.burning or def.name .. '_top_burning_animated.png'
   if not def.damage_radius then def.damage_radius = def.radius * 2 end

   minetest.register_node(':' .. name, {
      description = def.description,
      tiles = {tnt_top, tnt_bottom, tnt_side},
      is_ground_content = false,
      groups = {dig_immediate = 2, mesecon = 2, tnt = 1, flammable = 5},
      sounds = default.node_sound_wood_defaults(),
      after_place_node = function(pos, placer)
         if placer:is_player() then
            local meta = minetest.get_meta(pos)
            meta:set_string('owner', placer:get_player_name())
         end
      end,
      on_punch = function(pos, node, puncher)
         if puncher:get_wielded_item():get_name() == 'default:torch' then
            if minetest.check_player_privs(puncher, { fire = true }) then
               minetest.swap_node(pos, {name = name .. '_burning'})
               minetest.registered_nodes[name .. '_burning'].on_construct(pos)
               minetest.log('action', puncher:get_player_name() ..
                  ' ignites ' .. node.name .. ' at ' ..
                  minetest.pos_to_string(pos))
            end
         end
      end,
      on_blast = function(pos, intensity)
         minetest.after(0.1, function()
            tnt.boom(pos, def)
         end)
      end,
      mesecons = {effector =
         {action_on =
            function(pos)
               tnt.boom(pos, def)
            end
         }
      },
      on_burn = function(pos)
         minetest.swap_node(pos, {name = name .. '_burning'})
         minetest.registered_nodes[name .. '_burning'].on_construct(pos)
      end,
      on_ignite = function(pos, igniter)
         minetest.swap_node(pos, {name = name .. '_burning'})
         minetest.registered_nodes[name .. '_burning'].on_construct(pos)
      end,
   })

   minetest.register_node(':' .. name .. '_burning', {
      tiles = {
         {
            name = tnt_burning,
            animation = {
               type = 'vertical_frames',
               aspect_w = 16,
               aspect_h = 16,
               length = 1,
            }
         },
         tnt_bottom, tnt_side
         },
      light_source = 5,
      drop = '',
      sounds = default.node_sound_wood_defaults(),
      on_timer = function(pos, elapsed)
         tnt.boom(pos, def)
      end,
      -- unaffected by explosions
      on_blast = function() end,
      on_construct = function(pos)
         minetest.sound_play('tnt_ignite', {pos = pos})
         minetest.get_node_timer(pos):start(4)
         minetest.check_for_falling(pos)
      end,
   })
end

tnt.register_tnt({
   name = 'tnt:gunpowder_case',
   description = 'Gunpowder case',
   radius = tnt_radius,
})
